# EditorApplication.ProjectWindowItemInstanceCallback

> Delegate to be called for every visible list item in the ProjectWindow on every OnGUI event. Use this if you if you want to extend the functionality of the Project window. For example, to display information or tools relating to the assets or sub-assets that are visible.

## Definition

* **Type:** Delegate
* **Namespace:** [UnityEditor](/engine/6000.5/script-reference/unityeditor.md)
* **Assembly:** UnityEditor.CoreModule

> **Warning:**
>
> **Removed.** ProjectWindowItemInstanceCallback is obsolete. Use ProjectWindowItemByEntityIdCallback instead.

```csharp
public delegate void EditorApplication.ProjectWindowItemInstanceCallback(int instanceID, Rect selectionRect)
```

## Remarks

Additional Resources: [EditorApplication.ProjectWindowItemCallback](/engine/6000.5/script-reference/unityeditor/editorapplication/projectwindowitemcallback.md), [EditorApplication.projectWindowItemInstanceOnGUI](/engine/6000.5/script-reference/unityeditor/editorapplication/projectwindowiteminstanceongui.md).